Highly efficient removal of radioactive uranium on polyaniline modified carbon nanofiber composites

Abstract

In this article, polyaniline modified carbon nanofiber (PANI@CNF) composites were synthesized by in situ polymerization technique, and applied to highly efficient removal of radioactive uranium (U(VI)) from aqueous solutions. The prepared materials had abundant functional groups and excellent physical and chemical properties, which was confirmed by scanning electron microscope (SEM), transmission electron microscope (TEM), X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR) and X-ray photoelectron spectroscopy (XPS). The adsorption of U(VI) from aqueous solutions as a function of pH, ionic strength, reaction time and temperature on the materials were investigated by batch experiments. The elimination of U(VI) was strongly dependent on pH but independent of ionic strength, indicating that the interaction was mainly dominant by inner-sphere surface complexation. The adsorption kinetics were well simulated by pseudo-second-order model and reached reaction equilibrium within 30 min. The adsorption isotherms were well described by Langmuir isotherm model, implying that the elimination of U(VI) was monolayer coverage. At pH=5.0 and T =298 K, the maximum adsorption capacity of U(VI) on PANI@CNF (319.4 mg/g) was higher than those of U(VI) on CNF (133.9 mg/g), which was attributed to the synergistic effects between oxygen functional groups and nitrogen functional groups. Such a facile preparation method and efficient removal performance highlighted the application of PANI@CNF as a candidate for rapid and efficient radionuclide contamination’s elimination in practical applications.